The utility of antibodies in the therapy of clinically relevant diseases is well acknowledged. One of the primary dangers of these antibodies is the risk of an immune response by the patient, which receives the antibody, e.g., that the patient will make antibodies to the therapeutic antibodies.
Generally, previous research has focused on the risk associated with the addition of a mouse-based antibody to a human, resulting in the human patient launching an immune response against the mouse-based antibody. This immune response has also been termed a HAMA response, for “human anti-murine antibody.”
One attempt to limit this HAMA response is described in U.S. Pub. No. 20040005630 to Gary Studnicka (Published Jan. 8, 2004) herein incorporated in its entirety by reference. This publication discloses possible methods for how one might compare sequences, on an amino acid level, in order to determine which amino acids one might be able to change without reducing the affinity of the antibody, while simultaneously reducing the immunogenicity of the antibody so that one could administer the altered antibody to heterologous species. This reference suggests that the way to overcome the problem of a HAMA response is to make a residue by residue comparison of a working antibody to a consensus sequence. Particular amino acid positions that are exposed to solvent are then changed, if the residue is not involved in binding and if that residue is highly or moderately conserved in a human consensus sequence.
Others have attempted to determine whether or not VH gene usage is correlated with autoimmune diseases in general. These attempts have had little success. One such attempt was made by Huang et al. (Clin. Exp. Immunol. 112:516-527, (1998)). Huang et al. attempted to determine if there was some correlation between VH usage in patients with rheumatoid arthritis. Previous studies had resulted in conflicting results. Huang et al. looked at eight different VH3 genes and three different VH4 genes. However, their conclusion was that usage of individual VH genes in peripheral blood B cells was not affected by the disease. Huang et al. concluded that while there may be some VH genes that are preferentially used in rheumatoid factors, the overall representation of VH genes in the peripheral B cells is not altered. Moreover, these experiments were limited to generalized autoimmune problems.
The complexities in attempting to reduce immunogenicity are numerous. For example, several factors to be considered include the following: murine constant regions, V-region sequences, human immunoglobulin allotypes, unusual glycosylation, method of administration, frequency of administration, dosage of antibody, patient's disease status, patient's immune status, patient's MHC haplotype, specificity of antibody, cell surface or soluble antigen, degree of aggregation of the biologic being administered, formation of immune complexes with antigen, complement activation by antibody, Fc receptor binding by antibody, inflammation and cytokine release. (Mike Clark, Immunology Today, August 2000). However, Clark noted that some of the immunogenicity issues associated with V-region sequences can be altered by humanization.
Several studies have addressed polymorphisms and repertoire expression of V genes, sometimes in relation to ethnicity, age or gender. These reports relied on a single or very few donors (Hufnagle et al., Ann N Y Acad. Sci.; 764:293-295 (1995); Demaison et al., Immunogenetics, 42:342-352 (1995); Wang et al., Clin Immunol., 93:132-142 (1999); Rao et al., Exp Clin Immunogenet., 13:131-138 (1996); Brezinschek et al., J. Immunol., 155:190-202 (1995); and Rassenti et al., Ann N Y Acad. Sci., 764:463-473 (1995)), analyzed leukemia or autoimmune patients (Dijk-Hard et al., J. Autoimmun. 12:57-63 (1999); Logtenberg et al., Int Immunol., 1:362-366 (1989); Dijk-Hard et al., Immunology, 107:136-144 (2002); Johnson et al., J. Immunol., 158:235-246 (1997)), focused on a limited number of genes (Pramanik et al., Am J Hum Genet., 71:1342-1352 (2002); Rao et al., Exp Clin Immunogenet., 13:131-138 (1996); Huang et al., Mol. Immunol., 33:553-560 (1996); and Sasso et al., Ann N Y Acad. Sci., 764:72-73 (1995)), or categorized VH gene use by family (Hufnagle et al., Ann N Y Acad. Sci., 764:293-295 (1995); Rassenti et al., Ann N Y Acad. Sci., 764:463-473 (1995); and Logtenberg et al., Int Immunol., 1:362-366 (1989); Ebeling et al., Int Immunol., 4:313-320 (1992)).
Unfortunately, even when the HAMA response is eliminated, therapeutic antibodies can still elicit an immune response in patients. In other words, the antibody can elicit a human anti-human antibody (HAHA) response. This response can limit the antibodies' efficacy and can negatively affect their safety profile in the worst-case scenario. As an example, the fully human phage display-derived anti-TNF antibody HUMIRA® (Abbott Laboratories) unexpectedly provokes a HAHA response in approximately 12% of patients on monotherapy and about 5% in combination therapy with the methotrexate. Thus, while attempts have been made in overcoming the risks associated with a HAMA response, little has been done to address HAHA response issues.